How to use the glow wire test apparatus to do the glow wire testing

The glow wire test apparatus simulates that parts of insulation materials or other solid combustible materials that are prone to flame propagation inside the equipment may ignite due to the glow wire or glow element. Under certain conditions, such as fault current flowing through wires, component overload, and poor contact, certain components may reach a certain temperature and cause nearby parts to ignite.

The working principle of the hot wire test device is to specify the material Φ 4 mm nickel chromium wire (U-shaped hot wire head) is heated with high current to the specified temperature (300 ℃~1000 ℃) for testing, and then the test object is burned horizontally at the specified pressure (1.0N) for 30 seconds. The ignition hazard of the finished electrical and electronic equipment is determined by determining whether the test object and the bedding material ignite or hold on for a long time; After the test is completed, record the ignition time, ignition time (Ti), flame extinction time (Te), and flammability index (GWFI).

Glowing wire head: A sheathed fine wire thermocouple with a nominal diameter of 0.5mm is used to measure the temperature of the glowing wire. The wires are nickel chromium and nickel aluminum (K-type) wires, suitable for continuous operation at temperatures up to 960 ℃. Their welding points are located inside the armor sleeve, which is a thermocouple used to measure the temperature of the glowing wire. The metal of the armor sleeve can withstand a temperature of at least 1050 ℃.

Glow wire testing is a flame retardant performance test used in the electrical and electronic product industry to determine the stability of electronic products during operation. The Glow Wire Testing is a physical experiment aimed at testing the stability of electronic and electrical products during operation. The hot wire itself is actually a fixed specification resistance wire ring, which needs to be electrically heated to the specified temperature during the test, so that the top of the hot wire contacts the sample for the standard required time, and then its state is observed and measured. The testing range depends on the specific test procedure.

Glow wire testing method:
IEC 60335-1 specifies the standard for glow wires in household appliances, with the latest version being its Edition 5.0 2010-05. However, the specific hot wire test method is mainly reflected in specifications such as IEC 60695-2-10.

The hot wire test is achieved by heating the element to a predetermined temperature. The heating element is called a glow wire. Figure 3 is an example of the heating element used in the glow wire test. The sample to be tested is fixed in place, and cotton paper is placed directly under the sample. After reaching the predetermined temperature, press the hot wire onto the sample with a force of 1N for 30 seconds. If combustion occurs within 30 seconds, record the duration, flame height, and whether material droplets ignite the cotton paper.
Glow wire testing can be conducted on both terminal products and raw material samples. There are slight differences in the terminology used to define compliance in both cases.

GWT is abbreviated as Glow Wire Test (IEC 60695-2-11). Use GWT when conducting a glow wire test on the end product. The results of the experiment are either “passed” or “failed” at the given temperature. If the sample does not ignite or automatically extinguishes within 30 seconds after removing the heating element, and if dripping occurs and the dripping material does not ignite the cotton paper, it is considered “passed”.

GWFI represents the Glow Wire Flammability Index (IEC 60695-2-12). It is an attribute related to the raw materials used in the final product. This attribute is determined by conducting a hot wire test on a raw material sample of a given thickness. GWFI is the highest temperature at which the hot wire automatically extinguishes within 30 seconds after the material does not ignite or the heating element is removed.

GWIT represents the Glow Wire Ignition Temperature (IEC 60695-2-13). It is an attribute related to the raw materials used in the final product. This attribute is determined by conducting a hot wire test on a raw material sample of a given thickness. GWIT is the minimum temperature at which the material ignites and burns for more than 5 seconds when the heating element comes into contact with the sample.

Experimental requirements for ignition temperature testing of insulation materials:
In addition to the provisions of Chapter 8 of GB/T 5169.10-2006, unless otherwise specified, the top of the hot wire should be applied to the surface of the test sample that may be subjected to thermal stress during normal use. The hot wire should be kept as horizontal as possible. When more than one point is tested on the same test sample, it should be noted that the deterioration caused by the previous test should not affect the results of the subsequent tests.

When there is no detailed regulation on the area where the equipment is subjected to thermal stress during normal use, the top of the glow wire should be applied to the thinnest part of the test sample, and it is best not to be less than 15mm from the upper edge of the test sample. During the experiment, the test sample should be fixed on the experimental device, but additional mechanical stress should not be transmitted to the test sample.

Evaluation of test results:
Unless otherwise specified in relevant specifications, if the test sample does not burn or burn, or if all of the following conditions are met, it is considered to have passed the hot wire test:
a) If the flame or heat of the test sample extinguishes within 30 seconds after removing the ignition wire, i.e. test+30 seconds
b) When using the bottom layer of the specified packaging silk paper, the silk paper should not ignite.

The ZRS-3H Glow-wire Test Apparatus is according to IEC60695-2-1, IEC60695-2-10, IEC60695-2-11, IEC60695-2-12, IEC60695-2-13 (GB/T5169.10, GBT5169.11, GBT5169.12, GB/T5169.13) < Basic testing methods of Glow wire, basic testing methods of Glow wire device>, UL 746A, IEC829, DIN695 and VDE0471.

ZRS-3H Glow-wire Test Apparatus

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